63EuEuropium151.9641[Xe] 4f⁷ 6s²
lanthanide

Europium

Europium is a chemical element with symbol Eu and atomic number 63. It was isolated in 1901 and is named after the continent of Europe. It is a moderately hard, silvery metal which readily oxidizes in air and water.

Properties

At a glance

Atomic number
63
Atomic mass
151.9641 u
Phase
Solid
Density
5.264 g/cm³
Melting point
1,099 K
Boiling point
1,802 K
First ionization energy
547.1 kJ/mol
Electronegativity
1.2
Electron affinity
11.2 kJ/mol
Molar heat capacity
27.66 J/(mol·K)
Period
6
Appearance
Unavailable

Conditions and isotopes affect measured properties. Some properties of short-lived elements are predicted. Electronegativity uses the Pauling scale.

Electronic structure

Europium’s orbitals use a hydrogen-like approximation. Every orbital of each visible subshell is shown: in Shapes as the surface holding half its probability, with light and dark shades for opposite signs of the wavefunction; in Cloud as dots where its electrons are likely to be. Sizes are stepped by shell, like the Shell model.

Electrons by shell
Electron configuration

54 is the [Xe] core total across five shells.

Preparing the orbital view…

63 protons90 neutrons

Europium-153: its most common form in nature, or its longest-lived if it has none. The nucleus is drawn far too big: it’s about 100,000 times smaller than the atom.

States of matter

Turn up the heat

298 KK stands for kelvin, the temperature scale used in science. It starts at absolute zero (0 K), the coldest temperature possible, so it has no negative numbers and no degree sign.

A step of 1 K is the same size as 1 °C, so the two scales are always 273.15 apart. Fahrenheit is different: its degrees are smaller and it starts elsewhere, so water freezes at 273.15 K, 0 °C and 32 °F.25 °C · 77 °FSolid

At this temperature, europium is a solid.

At normal atmospheric pressure (1 atm). The temperature scale is logarithmic. The particle box is schematic: real samples hold vastly more atoms, and spacing and speeds are not to scale.

Ionization energy

Pull the electrons off

Eu

EuNeutral atom · no charge

A neutral europium atom. Removing its first electron takes 547 kJ/mol.

Europium’s outer shell holds 2 electrons. Electron 3 is the first from an inner shell: it sits closer to the nucleus with less shielding, so removing it takes 2.2× as much energy as the one before. Each dashed line on the chart marks another jump, into a shell even closer to the nucleus.

Shell 1Shell 2Shell 3Shell 4Shell 5Shell 6MeasuredEstimated or calculatedEnergy in kJ/molkJ/mol (kilojoules per mole) is the energy to remove that electron from every atom in a mole of them: about 602 sextillion (6.02 × 10²³) atoms. For a single atom, divide by 96.485 to get electronvolts (eV). Europium’s first electron takes about 5.7 eV.
1001,00010,000100,0001,000,00010,000,000Shell 5Shell 4Shell 3Shell 2×2.2×1.1×1.7×2.2×4.1151015202530354045505560
Show the values as a table
ElectronShellEnergy (kJ/mol)× previousValue
16547–Measured
261,0852Estimated
352,3972.2Estimated
454,1431.7Estimated
556,0981.5Estimated
658,5871.4Calculated
7510,1311.2Calculated
8511,5781.1Calculated
9513,8941.2Calculated
10515,5341.1Calculated
11417,6571.1Calculated
12420,5511.2Calculated
13423,4461.1Calculated
14425,3761.1Calculated
15427,1121.1Calculated
16430,0071.1Calculated
17433,2301.1Estimated
18449,9791.5Calculated
19453,3561.1Calculated
20456,9261.1Calculated
21460,7861.1Calculated
22464,3561.1Calculated
23468,4081.1Calculated
24472,8461.1Calculated
25476,7061.1Calculated
26480,8551.1Calculated
27484,8111Calculated
284100,0551.2Calculated
294104,0111Calculated
304108,4501Calculated
314112,5981Calculated
324120,5101.1Calculated
334125,0451Calculated
344135,6581.1Calculated
354140,4881Estimated
363240,7311.7Calculated
373249,9931Calculated
383260,2211Calculated
393270,8341Calculated
403281,1581Calculated
413291,5791Calculated
423305,6661Calculated
433316,3751Calculated
443327,8571Calculated
453338,6641Calculated
463368,8631.1Calculated
473378,3191Calculated
483388,9321Calculated
493398,5811Calculated
503424,5351.1Calculated
513435,4381Calculated
523456,2791Calculated
533466,7961Calculated
5421,049,7602.2Calculated
5521,076,1011Calculated
5621,105,4321Calculated
5721,132,6411Calculated
5821,227,1001.1Calculated
5921,259,1341Calculated
6021,298,8861Calculated
6121,325,5711Calculated
6215,390,2434.1Calculated
6315,511,3041Calculated

Successive ionization energies of gas-phase atoms and ions from the NIST Atomic Spectra Database. Solid bars are measured; hatched bars were estimated from nearby measurements or calculated from quantum theory, as is usual for highly charged ions. Electrons are taken from the outermost shell first, a simplification: electrons in different subshells of the same shell also differ in energy. On the log scale each gridline is 10 times the one below.

Compared with other elements

How does it compare?

EuropiumOther lanthanidesOther elements

Density

5.26 g/cm³35th lowest of 99

Eu

Melting point

1,099 K43rd lowest of 96

Eu

Boiling point

1,802 K36th lowest of 97

Eu

Electronegativity

1.222nd lowest of 96

Eu

First ionization energy

547 kJ/mol17th lowest of 99

Eu

Elements 1–99 from the reference data; heavier elements are left out because only a few atoms have ever been made, so their bulk properties are predictions. First ionization energies come from NIST. Density uses a logarithmic scale, because gases are around a thousand times less dense than solids; gas densities are at 0 °C and 1 atm. Melting and boiling points are at normal pressure. Everyday temperatures and light sources in the pictures are approximate. Hover over a dot to see the element, or click it to compare.

Keep exploring

Explore the stories, imagery, and reference data in more depth. Properties with no value in the reference are marked unavailable.